Ceramic matrix composite airfoil cooling

A method for forming an airfoil for a gas turbine engine, the method comprising:

• forming a plenum preform from a ceramic matrix composite (CMC) material;
• forming a filler pack preform from the CMC material;
• preparing a plurality of airfoil plies, the plurality of airfoil plies formed from the CMC material;
• laying up the plenum preform, the filler pack preform, and the plurality of airfoil plies to form an airfoil preform assembly, the airfoil preform assembly including
• opposite pressure and suction sides extending radially along a span,
• opposite leading and trailing edges extending radially along the span, the pressure and suction sides extending axially between the leading and trailing edges, the leading edge defining a forward end of the airfoil preform assembly, the trailing edge defining an aft end of the airfoil preform assembly,
• a trailing edge portion defined adjacent the trailing edge, the trailing edge portion extending axially over a length, and
• a plenum defined within the airfoil preform assembly forward of the trailing edge portion;
• and
• processing the airfoil preform assembly to produce the airfoil,
• wherein the pressure and suction sides define an outer surface of the airfoil, and
• wherein a cooling passage is defined within the airfoil, the cooling passage defined from the plenum to the trailing edge of the airfoil, the cooling passage defined proximate the suction side of the airfoil, the cooling passage comprising:
• a first cavity extending radially within the trailing edge portion;
• a second cavity defined aft of the first cavity, the second cavity extending radially within the trailing edge portion;
• a crossover aperture defined from the plenum to the first cavity;
• a channel defined from the first cavity to the second cavity, the channel extending axially between the first and second cavities;
• and
• an ejection aperture defined from the outer surface of the airfoil to the second cavity;
• wherein each of the airfoil plies, the plenum plies, and the filler pack comprise a ceramic matrix composite material such that the airfoil is formed from the ceramic matrix composite material, and
• wherein the first cavity, the second cavity, and the channel are defined in the filler pack such that the first cavity, the second cavity, and the channel are separated from the outer surface by the airfoil plies.

A method for forming an airfoil for a gas turbine engine, the method comprising:

• laying up a plurality of airfoil plies, a plurality of plenum plies, and a filler pack to form an airfoil preform assembly, the airfoil preform assembly including
• opposite pressure and suction sides extending radially along a span,
• opposite leading and trailing edges extending radially along the span, the pressure and suction sides extending axially between the leading and trailing edges, the leading edge defining a forward end of the airfoil preform assembly, the trailing edge defining an aft end of the airfoil preform assembly,
• a trailing edge portion defined adjacent the trailing edge, the trailing edge portion extending axially over a length, and
• a plenum defined within the airfoil preform assembly forward of the trailing edge portion;
• and
• processing the airfoil preform assembly to produce the airfoil,
• wherein the plurality of airfoil plies, the plurality of plenum plies, and the filler pack are
• formed from a ceramic matrix composite (CMC) material,
• wherein the filler pack is positioned between the airfoil plies and the plenum plies in the trailing edge portion of the airfoil preform assembly, and
• wherein a plurality of cooling passages is defined within the airfoil, each cooling passage defined from the plenum to the trailing edge of the airfoil, and defined proximate the suction side of the airfoil, each cooling passage comprising:
• a first cavity extending radially within the trailing edge portion;
• a second cavity defined aft of the first cavity, the second cavity extending radially within the trailing edge portion;
• a crossover aperture defined from the plenum to the first cavity;
• a channel defined from the first cavity to the second cavity, the channel extending axially between the first and second cavities;
• and
• an ejection aperture defined from the outer surface of the airfoil to the second cavity;
• wherein each of the airfoil plies, the plenum plies, and the filler pack comprise a ceramic matrix composite material such that the airfoil is formed from the ceramic matrix composite material, and
• wherein the first cavity, the second cavity, and the channel are defined in the filler pack such that the first cavity, the second cavity, and the channel are separated from the outer surface by the airfoil plies.